Others have said it will be available when you hit your mark. I too am anxiously awaiting to see what happens when we hit our date. Let us know what happens tomorrow..
My understanding is that if you have a valid ticket linked to your MDE account you will see the next 30 days as available to make FP+ reservations (which is what is available for off site guests). If you have an on site resort stay linked to your MDE account, at the 60 day mark you will see FP+ availability for your resort dates.
Mine is doing the same thing right now. I think I'm 64 days out.
I I just spoke with a CM in technical support and he told me the 30 days we see is for the offsite guests. Tomorrow my days should appear because I am staying onsite.